Slip gives the difference between Driving wheel speed and Driven wheel speed as a percent of the speed of the driven wheel. Slip can be both positive and negative. The following applies:

 

·0 % Slip - The Driving and Driven wheels are turning at the same speed.

·10% Slip - The Driving wheels are turning 10% faster than the Driven wheels.

·100% Slip - The Driving wheels are turning twice as fast as the Driven wheels.

·-10% Slip - The Driving wheels are turning slower than the Driven wheels (eg hard braking).

·-100% Slip - The Driven wheels are turning but the driving wheels are not (eg rear brakes locked up).

 

When calculating Slip, the Driving and Driven Speed Sources are used. For the Slip calculation to work a Driving AND Driven speed source need to be setup.

 

The Slip runtime value can be found in the Misc tab of the Runtime Values window (F12 key). Slip is also an axis parameter options and can be selected for a 3D table using the Axis Setup menu.

 

Slip Example

A typical application of Slip Calculation would be as a form of traction control. One or two wheel speed sensors could be fitted to the driving wheels (front or real wheel drive) and one (or two) sensors could be fitted to the driven wheels. Slip could then be used as an axis on the GP RPM Limit table to invoke an RPM limit when excessive slip (wheel spin) was detected. Alternately the boost level could be decreased to decrease power.